[Lorddrinkalot]

Hey guys,

First, I uploaded my case to my GitHub:
https://github.com/Lorddrinkalot/openfoam_forum

I am trying to simulate the flow through a fusion blacket using a very simple geometry, L_shape.

I am using the bouyantPimpleMhdFoam solver. The bouyantPimpleFoam can also be used for cases without MHD, and the same problem is present.
EquationofState is Boussinesq.


I have split my Simulation into simple steps for better troubleshooting.
Starting with the normal flow with no Heat source and no magnetic field, this case is converging and working fine.

For the second part, I've added the FvOption file for my Heat source. However, the Simulation is diverging and I'm still trying to pinpoint the issue. I thought it would be beneficial to share it here to receive some valuable feedback from you all. Your insights are highly appreciated.

I think that my boundary conditions (p_rgh and U) are not "good enough" anymore for the second part with the heat source switched on. (have some images in the attachments)

Another option would be the mesh; however, checkMesh says the mesh is ok, and I also agree with this. Also, when I refine the mesh, the problem stays.

Best regards
Christoph

/*---------------------------------------------------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  2312                                  |
|   \\  /    A nd           | Website:  www.openfoam.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
Build  : _c39a0f64-20231220 OPENFOAM=2312 version=2312
Arch   : "LSB;label=32;scalar=64"
Exec   : checkMesh
Date   : Jun 17 2024
Time   : 12:35:35
Host   : DESKTOP-FNK6QBM
PID    : 11968
I/O    : uncollated
Case   : /home/christoph/OpenFOAM/christoph-v2312/run/L_shape
nProcs : 1
trapFpe: Floating point exception trapping enabled (FOAM_SIGFPE).
fileModificationChecking : Monitoring run-time modified files using timeStampMaster (fileModificationSkew 5, maxFileModificationPolls 20)
allowSystemOperations : Allowing user-supplied system call operations

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Create time

Create mesh for time = 0

Check mesh...

Time = 0

Mesh stats
    points:           150381
    faces:            426100
    internal faces:   401900
    cells:            138000
    faces per cell:   6
    boundary patches: 5
    point zones:      0
    face zones:       0
    cell zones:       0

Overall number of cells of each type:
    hexahedra:     138000
    prisms:        0
    wedges:        0
    pyramids:      0
    tet wedges:    0
    tetrahedra:    0
    polyhedra:     0

Checking topology...
    Boundary definition OK.
    Cell to face addressing OK.
    Point usage OK.
    Upper triangular ordering OK.
    Face vertices OK.
    Number of regions: 1 (OK).

Checking patch topology for multiply connected surfaces...
    Patch               Faces    Points     Surface topology
    inlet               600      651      ok (non-closed singly connected)
    outlet              600      651      ok (non-closed singly connected)
    Wall_out            8100     8401     ok (non-closed singly connected)
    Wall_side           9200     9702     ok (non-closed singly connected)
    Wall_inside         5700     5921     ok (non-closed singly connected)
    ".*"                24200    24202    ok (closed singly connected)


Checking faceZone topology for multiply connected surfaces...
    No faceZones found.

Checking basic cellZone addressing...
    No cellZones found.

Checking basic pointZone addressing...
    No pointZones found.

Checking geometry...
    Overall domain bounding box (0 0 0) (1.133 2.135 0.1616)
    Mesh has 3 geometric (non-empty/wedge) directions (1 1 1)
    Mesh has 3 solution (non-empty) directions (1 1 1)
    Boundary openness (-2.61002e-16 -2.41706e-18 5.65942e-15) OK.
    Max cell openness = 1.53505e-16 OK.
    Max aspect ratio = 6.88459 OK.
    Minimum face area = 4.19083e-05. Maximum face area = 0.000527534.  Face area magnitudes OK.
    Min volume = 5.96145e-07. Max volume = 2.84165e-06.  Total volume = 0.229287.  Cell volumes OK.
    Mesh non-orthogonality Max: 0 average: 0
    Non-orthogonality check OK.
    Face pyramids OK.
    Max skewness = 1.66477e-13 OK.
    Coupled point location match (average 0) OK.

Mesh OK.

End

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  v2212                                 |
|   \\  /    A nd           | Website:  www.openfoam.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       volScalarField;
    object      p;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions      [1 -1 -2 0 0 0 0];

internalField   uniform 0;

boundaryField
{
    inlet
    {
		type			zeroGradient;
        //type            fixedFluxPressure;
		//value			uniform 0;
    }
    outlet
    {
		//type            totalPressure;
        //p0              uniform 0;
        //U               U;
        //rho             rho_0;
		
		
	    type            fixedValue;
        value           uniform 0;
		
	    //type            fixedFluxPressure;
		//value			uniform 0;
        //type            inletOutlet;  //outletInlet
		//inletValue		uniform 0;
    }
    Wall_side
    {
		type			zeroGradient;
    }
    Wall_out
    {
		type			zeroGradient;
    }
    Wall_inside
    {
		type			zeroGradient;
    }


}


// ************************************************************************* //

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  v2212                                 |
|   \\  /    A nd           | Website:  www.openfoam.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       volVectorField;
    object      U;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions      [0 1 -1 0 0 0 0];

internalField   uniform (0 0 0);

boundaryField
{
    inlet
    {
        type            fixedValue;
        value           uniform (0.02 0 0);
    }
    outlet
    {
		type    zeroGradient;
        //type          pressureInletOutletVelocity;
		//value			uniform (0 0 0);
    }
    Wall_side
    {
        type            noSlip;
    }
    Wall_out
    {
        type            noSlip;
    }
    Wall_inside
    {
        type            noSlip;
    }

}


// ************************************************************************* //